These are some patterns I’ve found in Rust that tend to make error handling code more legible/less noisy.

Handling errors

If you only care about one case in an error, instead of being forced to match against all errors, do this:

if let Some(val) = returns_option() {
    // do something
}

If the value that is returns doesn’t matter, then you can do this:

if returns_option().is_some() {
    // do something
}

There’s corresponding versions for the other values as well: Result::{is_err, is_ok}, Option::{is_some, is_none}

If you expect the error to never happen, or if it happens you can’t handle it, you can just unwrap or expect it.

• unwrap just panics over an error. So if you do this:

let x = returns_option().unwrap();

that would be equivalent to this:

let x = match returns_option() {
    Some(x) => x,
    None => panic!("some reason why it errored here"),
};

• expect allows you to change the panic message, you should write there what your expectation was for that error

let retcode = execute_file("path/to/file").expect("file should be executable");

Propagating errors

fn func(x: &str) -> Result<&str, Error> {
    // instead of:
    let x = match returns_result(x) {
        Ok(other) => other,
        Err(err) => return err,
    };

    // do:
    let x = returns_result(x)?;
}

Sometimes though, the Result or Option returns by the function might not be 1-to-1 with the functions you’re propagating the error from, in those cases you can either use let else idiom:

let Ok(other) = returns_result(x) else {
    return None;
}

Or you can also convert from a Result to an Option or vice versa with these methods: Result::{ok, err} and Option::ok_or to convert to the appropriate type

fn func(x: &str) -> Option<&str> {
    let other = returns_result().ok()?;
}

If these are not sufficient, you might want to change the Error or Ok values so you can “massage” it into working, these functions are Result::{map_err, map_ok} and Option::map_or. You can use them like this:

let other = returns_result().map_err(|e| /* massage the value here */)?;